The problem is that these include too many unworthy stories: for example, stories that could have been written largely by AI (whether or not they were); that include egregious grammatical or other errors, even in their titles; or that violate Medium's guidelines. And curators aren't catching them.
These unworthy stories can leave the suspicion that some nommers are playing favorites, are in over their heads, or just don't care about quality and curators are rubber-stamping their decisions. And there's no effective way to report these, in part because, for example, the use of AI is hard to prove and if you report it to Support, that's what you'll hear.
In addition, some nommers are setting their own guidelines that exclude stories for reasons that make no sense and seem hurtful to Medium: e.g, one nommer who specializes in an area I often write in says (absurdly in my view) they won't open most stories with a less than 6 minute reading time because in their experience they have less "depth" than 6-minute stories. This guideline encourages people to pad stories and violates the golden write of writing: Say what you have to say and then stop, whether it's 4 minutes or 6 minutes. If you write a great 4-minute story you have to pray some other nommer will see it.
I never had any problems with a great story not getting boosted until after August when pubs started posting lists of their boosted stories (or members bragged about theirs) and you could see that what got boosted instead was a story that appeared AI written or was full of those grammatical or other errors. It's vastly demotivating.